OK, after looking at VK's version, I was embarrassed that I ignored the sky. So, I pushed the highlight slider to 100, and used the color editor and picked a point in the center of the sky, and adjusted rotation quite a bit to change the hue. Small tweaks to saturation and I had what looks like to me a blue sky with a slight amount of haze. Certainly pushing my skill limit here, but it's interesting to experiment.